A touch location detecting device is a device for detecting a user's touch at a specific location on a panel that is installed overlappingly on a display screen or provided separately from the display screen. Information on the presence and location of a touch on the panel are utilized for the operation control, screen manipulation and the like of a computer system that incorporates therein the touch location detecting device.
A method for detecting a touch location can be largely classified into two categories: a continuous location detecting type and a discrete location detecting type. The continuous location detecting method or an analog method measures a continuous change in, such as, optical or electrical characteristics caused by a change in user's touch location on a panel, and calculates the touch location based on the measured value. On the other hand, the discrete location detecting method, a so-called matrix type method, detects the presence of a user's touch on each of the sensing areas that are arranged at a plurality of locations on a panel to thereby find out the touch location.
While the continuous location detecting method is capable of detecting the touch location in a precise and elaborate manner, it requires a separate process or additional hardware for the calculation of the touch location. Meanwhile, the discrete location detecting method has a limited touch location detecting resolution which is dependent on an arrangement pitch of sensing areas. However, the discrete location detecting type method has been widely used in various kinds of digital equipments due to its easiness in acquiring information on a touch location, which is done simply by detecting a touch on a specific sensing area.
The present invention relates to a touch location detecting panel for use in a touch location detecting device adopting the discrete location detecting type method set forth above. FIGS. 1 and 2 illustrate sensing area patterns that constitute a touch location detecting panel of a conventional discrete location detecting type, and a layered structure thereof, respectively.
Referring to FIG. 1, the conventional touch location detecting panel is comprised of a total of 3 layers: a vertical location sensing layer 10 for sensing a vertical location of a user's touch; a horizontal location sensing layer 20 for sensing a horizontal location of the user's touch; and a shielding layer 30 for shielding the vertical and horizontal location sensing layers 10 and 20 from electrical noises. These three layers 10, 20 and 30 are layered through adhesive layers 23 and 33 as shown in FIG. 2, and as a whole, they are adhered to the rear surface of a transparent window 40 through an adhesive layer 13.
The three layers 10, 20 and 30 mentioned above are constituted by a film layer 11, 21, and 31 as a base of pattern formation, and a pattern layer 12, 22, and 32 formed thereon, respectively, as shown in FIG. 2.
In the conventional touch location detecting device, the reason that the horizontal location sensing layer 20 and the vertical location sensing layer 10 are configured in separate layers is to minimize the number of connection lines connected to an external circuitry for detecting a touch at each location. For example, if sensing areas are arranged at an M-number of locations in a horizontal direction and at an N-number of locations in a vertical direction on the surface of a single film, a touch detecting circuit would require an (M×N)-number of channels for detecting a touch on each sensing area. However, if sensing patterns for sensing vertical and horizontal locations, respectively, are formed separately in different sensing layers 10 and 20 as depicted in FIGS. 1 and 2, only an (M+N)-number of channels are needed to detect a touch location with respect to an entire panel area.
Namely, the conventional touch location detecting panel shown in FIGS. 1 and 2 is configured in a manner that the vertical location sensing layer 10 and the horizontal location sensing layer 20 are layered separately in order to avoid the limit on the number of sensing areas by the number of channels in the touch detecting circuit.
In this case, however, the lamination thickness of the touch location detecting panel increases, and manufacturing cost of the detecting panel is increased accordingly. For instance, in case of a touchscreen, the pattern layers 12, 22, and 32 are formed by using transparent conductive materials such as TTO (Indium Tin Oxide). Unfortunately, however, the formation of the ITO pattern layers requires a costly process, and since the conventional touch location detecting panel has even two sensing layers 10 and 20 having such high manufacturing costs, total manufacturing cost is increased.
To solve the above-mentioned problems, there arises a need for a new technique capable of minimizing the number of channels connected to the touch detecting circuit while allowing an arrangement of a vertical and a horizontal location sensing pattern together on the surface of a single film.